1. Field of the Invention
The present invention generally relates to a stacked multilayer structure, and more specifically to a glass fiber layer embedded in a plastic film and not exposed to increase the reliability of a second circuit layer.
2. The Prior Arts
Please refer to FIG. 1 and FIGS. 2A to 2G. As shown in FIG. 1, the method S100 of manufacturing the stacked multilayer structure in the prior arts comprises the steps S110 to S160. FIGS. 2A to 2G are used to illustrate the method in more detail.
As shown in FIG. 2A, a substrate 10 is stacked with a first circuit layer 20 through the process of image transfer in the step S110. The first circuit layer 20 has a plurality of bumps 21. The step S120 is performed to press the plastic film 30 having a glass fiber layer 35 therein against the substrate 10 having the first circuit layer 20 thereon, as shown in FIGS. 2B and 2C. After pressed, the glass fiber layer 35 is obviously deformed because the first circuit layer 20 is not smooth.
In the step S130, the pressed plastic film 30 is polished until the bumps 21 are exposed such that part of the glass fiber layer 35 above the bumps 21 is removed and the remaining part of the glass fiber layer 35 is thus exposed, as shown in FIG. 2D. Next, in the step S140 as shown in FIG. 2E, a second metal layer 23 is formed on the resulting surface by evaporation or sputtering. The step S150 is performed to form a second circuit layer 25 from the second metal layer 23 by the process of image transfer such that the second circuit layer 25 is connected to the first circuit layer 20, as shown in FIG. 2F. Finally, the substrate 10 is removed in the step S160 to form the stacked multilayer structure, as shown in FIG. 2G.
One of the shortcomings in the prior arts is that the second metal layer 23 or the second circuit layer 25 is likely to peel off because the glass fiber layer is partly exposed and the adhesion between the glass fiber layer and the metal is considerably poor even the second metal layer 23 is formed by evaporation or sputtering. As a result, the yield and reliability greatly deteriorate. Therefore, it is needed to provide a new stacked multilayer structure to overcome the above problems in the prior arts.